Between September 1986 and September 1991, 44 patients with lung metastases originating from an osteosarcoma of an extremity were treated with: primary chemotherapy, simultaneous resection of primary and metastatic lesions (when feasible), and then further chemotherapy. After primary chemotherapy, lung metastases disappeared in 5 patients, whereas in 11 patients they remained surgically unresectable. All 16 patients received local treatment of the primary tumor only. In the remaining 28 patients simultaneous surgical treatment of the primary and the metastatic tumor was performed. The removal of metastatic lesions was complete in 25 and incomplete in 3 patients. With a median follow-up of 8 years (5.5-10.8) all 14 patients who never achieved a tumor-free status died. Of the 30 patients who achieved remission 5 (17%) remained continuously free of disease and 25 developed new metastases, associated with local recurrence in 4 cases. The 5-year overall survival for all 44 patients of the study was 14%, and the 5-year disease-free survival for the 30 patients who reached remission was 17%. These results are significantly worse than those achieved with the same chemotherapy protocol in 144 contemporary patients with localized disease at presentation (73% disease-free and 79% overall survival). We conclude that, despite aggressive chemotherapy which is successful in patients with localized disease, the prognosis remains very poor for patients with osteosarcoma of the extremities with lung metastases at presentation, and justifies the use of novel therapies.